This invention relates to electric cooking apparatus and is directed particularly to an electric cooking system including a common electric heat exchange cooking unit and a plurality of cooking receptacles for different cooking purposes which can be selectively inter-engaged with the common heat exchange cooking unit for use as desired in cooking various foods.
The use of electric hot plates or flat, electrically energized heating elements of one kind or another in either single heating element, portable form, or in electric ranges, is well known. See, for example, U.S. Pat. Nos. 726,241; 968,441; and 1,120,884 to Ayer; U.S. Pat. No. 2,850,616 to Hatch; and U.S. Pat. No. 2,872,560 to Bowles. Such electric hot plates or electric range heating elements or pads are designed for use with flat-bottom cooking pots or pans seated thereupon for heat exchange through the bottom. While versatile in usage, such heating of ordinary pots and pans is generally inefficient and uneven not only because intimate surface-to-surface contact cannot be achieved, but also because uniformity of face-to-face contact between the heating member and the bottom surface of the cooking receptacle being heated can rarely be achieved. This is true not only because flat-bottom cooking utensils, even if of the best quality, become uneven or lose their high degree of flatness at the bottom due to scrubbing and wear and tear after a short period of usage, which is often imperceptible to the eye, but also because the flat heating members, likewise being exposed to the wearing effects of utensils being placed on and being moved therefrom, soon losetheir flatness. The overall result of these deficiencies not only is uneven distribution of heat through the bottom of the cooking receptacle, which may result in hot spots or even burning at localized areas, but also inefficiency of heat transfer and wastage or uneconomical usage of electrical energy.
Another deficiency in electric hot plate cooking utensils heretofore devised resides in the design of the hot plate electric heating mechanism itself, resulting in uneven temperatures at the heat exchange surface and consequent hot spots and burning in the cooking utensil even with intimate contact for efficient heat transfer between the hot plate surface and the cooking utensil.